A Study of the Fundamental Science Underlying the Transport of Intense Femtosecond Laser Pulses in the Atmosphere

Download or read book A Study of the Fundamental Science Underlying the Transport of Intense Femtosecond Laser Pulses in the Atmosphere written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have identified and confirmed that ultrafast intense Ti-sapphire laser pulses after propagating through an optical medium self-transform into chirped white light laser pulses as manifested by the generation of supercontinuum. During the propagation of such pulses in air, self-focusing and filamentation take place together with strong field interaction with molecules in its path. Some important physical processes were studied. In particular, we observed a new type of fluorescence from the air molecules characteristic of intense field ionization and fragmentation unexpected from normal wisdom of plasma emission. An analytical tunnel ionization model of air molecules that agree with our experimental results was developed. It could be used in any theoretical modelling of such propagation. New techniques were developed to study the dynamics of filamentation. They allowed us to observed directly for the first time the signature of re-focusing The dependence of filamentation on various laser parameters such as the chirp, the divergence, etc. was also measured. Preliminary results agree with what we expect based on current knowledge of ultrafast nonlinear optics.